There was a custom in ancient China that people would pledge their love with a bunch of grass or a bundle of sprigs, as is told in the poetry of Shih-chin (詩經) and others. Why it developed into an emblem of love can be traced in the word "yakusoku" (約束). The bunch of grasses was originally a magical object in which the spirits of gods were meant to dwell, and this bunch of grasses turned into the token attributed as the power to summon one's sweet-heart whom one might wish to have as his compagny. "Yakusoku", i. e. "to bind" or "to bundle", therefore, came to mean "chigiri", i, e. "promise" or "engagement".